Little Sheep Mountain

The Little Sheep Mountain Inventoried Roadless Area covers 14,192 acres of mountainous, montane terrain in the Bridger-Teton National Forest at the head of the Green River in Sublette County, Wyoming. The land rises around Little Sheep Mountain itself, Gypsum Hill, Gypsum Park, and Red Hill — a sequence of sage-covered benches and forested ridges between the Wind River Range to the east and the lower Green River valley to the west. The watershed is the Lime Creek–Green River headwaters; water drains through Red Creek, South Fork Gypsum Creek, Moose Creek, and Dago Creek, and through a remarkable set of springs and warm-water features: Warm Spring, Stinky Spring, Gypsum Spring, and most notably Kendall Warm Spring, whose constant 85°F discharge feeds Brook Lake and supports an endemic biota found nowhere else.

Forest composition tracks elevation and aspect closely. Lower benches around Gypsum Hill and Red Hill carry Intermountain Mountain Sagebrush Steppe and Wyoming Basin Dwarf Sagebrush, with big sagebrush (Artemisia tridentata), hoary sagebrush (Artemisia cana), prairie-smoke (Geum triflorum), and arrowleaf phlox communities. Aspen draws (Rocky Mountain Aspen Forest) hold quaking aspen (Populus tremuloides) over sticky geranium (Geranium viscosissimum) and Canada buffaloberry (Shepherdia canadensis). Mid-slopes carry Central Rockies Douglas-fir Forest, Rocky Mountain Lodgepole Pine Forest, and Intermountain Mountain Mahogany Woodland; subalpine ridges hold Rocky Mountain Dry Subalpine Spruce-Fir Forest and Northern Rockies Subalpine Woodland and Parkland, where whitebark pine (Pinus albicaulis) — an IUCN endangered species — anchors exposed crests. Rocky Mountain Subalpine Streamside Woodland follows the creeks with streamside bluebells (Mertensia ciliata) and slender-sepal marsh-marigold (Caltha leptosepala); the alpine pockets above timberline hold cushion communities of moss campion (Silene acaulis), alpine bitterroot (Lewisia pygmaea), and Hooker's mountain-avens (Dryas hookeriana).

Wildlife relationships are organized vertically and around water. Clark's nutcracker (Nucifraga columbiana) caches whitebark pine seeds across the subalpine ridges, sustaining seed dispersal where wind and birds alone reseed the species. Wapiti (Cervus canadensis), moose (Alces alces), and mule deer (Odocoileus hemionus) feed in the sagebrush benches and subalpine meadows, with American black bear (Ursus americanus) following berry crops through summer. The Kendall Warm Spring system supports a unique year-round ice-free wetland community and supplies steady warm-water habitat downstream. Lewis's woodpecker (Melanerpes lewis) and Williamson's sapsucker (Sphyrapicus thyroideus) work the open aspen and pine; broad-tailed (Selasphorus platycercus) and rufous (S. rufus) hummingbirds feed at meadow paintbrush and skyrocket. Mountain whitefish (Prosopium williamsoni) and rainbow trout (Oncorhynchus mykiss) hold in the cold Green River and Lime Creek reaches. The black rosy-finch (Leucosticte atrata) — IUCN endangered — uses the alpine rock terrain at the upper edge of the area. Portions of this area fall within the potential range of several federally listed species; see the Conservation section for details.

A traveler moving up from the Green River into Little Sheep Mountain crosses sagebrush steppe alive with sandhill crane (Antigone canadensis) calls and meadowlark, climbs through aspen and Douglas-fir into closed lodgepole on the north slopes, and emerges in subalpine parkland under whitebark pine. Kendall Warm Spring runs without ice through the winter; steam rises off Brook Lake at first light.

The Little Sheep Mountain Roadless Area sits at the upper end of the Green River drainage in Sublette County, Wyoming, in country with one of the deepest documented human histories in the northern Rockies. "The Eastern Shoshone was the primary tribe in the Green River Basin in the years before the arrival of European and American explorers. The Shoshone traded and battled with the Ute tribe to the south and were allies of the Bannock Tribe to the west" [1]. The basin's geographic bottleneck at Trapper's Point — about six miles west of present Pinedale, where the Green and New Fork Rivers funnel migrating ungulates together — has been used by hunters for 7,000 years: "An archeological dig at this site revealed 7,000 year old charcoal pits and pronghorn bones, indicating that hunters have targeted wildlife at this critical place for millennia" [1].

The European-American history of the upper Green begins with the fur trade. "In 1812, Robert Stuart, a member of an expedition organized by John Jacob Astor … discovered South Pass," and "in 1823, Jedediah Smith and a team of young trappers, with the help of Crow Indians, rediscovered the pass as a route to the beaver-rich Green River Basin" [1]. Smith, William Ashley, and Andrew Henry organized the mountain-man rendezvous system: the first was held on Henry's Fork of the Green in 1825, and "a half dozen rendezvous were held in the upper Green River Basin near a historic site called Trapper's Point between 1833 and 1840" [1]. After the fur trade collapsed, the timber turned commercial: "In 1867 an entrepreneur named Charley Deloney contracted with the Union Pacific Railroad and set up a tie hack operation in what is now the Bridger-Teton National Forest along the Upper Green River. Between 1867 and 1869 a team of 30 men cut ties, skidded them to the Green River, and floated them 130 miles downstream to the town of Green River and the UP" [1]. Tie-hacking paused until 1895, then resumed under successive timber companies until 1952. Cattle ranching took hold in parallel: "The Green River Drift's first recorded use was in 1896 by the Upper Green River Cattle Association," whose members gathered cattle on the desert in spring and drove them north 58 miles up the river to summer pastures in what is now the Bridger-Teton National Forest, a "stock driveway" still in continuous use [2].

Federal protection of the upper Green came through the long sequence of forest-reserve consolidations on the eastern side of the Yellowstone region. The Yellowstone Forest Reserve was established in 1902, with A.A. Anderson appointed superintendent by President Theodore Roosevelt [3]. The U.S. Forest Service was created in 1905; the agency asked Sublette County ranchers to form grazing associations, and "forest grazing permits were issued in 1906" along the upper Green [2]. The high country at the head of the Green that includes Little Sheep Mountain was eventually consolidated into the Bridger National Forest, and the Bridger Wilderness — "a primitive area designated by Secretary of Agriculture Arthur Hyde in 1931 and established as wilderness when President Lyndon Johnson signed the Wilderness Act in 1964" — was set aside immediately east of the present Little Sheep Mountain Roadless Area [1]. Today the 14,192-acre Little Sheep Mountain Inventoried Roadless Area is administered by the Pinedale Ranger District of the Bridger-Teton National Forest under the 2001 Roadless Area Conservation Rule.

Vital Resources Protected

• Kendall Warm Spring and Endemic Aquatic Habitat: The roadless area holds the Kendall Warm Spring system — a year-round 85°F discharge into Brook Lake — along with Warm Spring, Stinky Spring, and Gypsum Spring. The roadless condition preserves the spring's undisturbed thermal hydrology and the small, fragile habitat that supports the federally Endangered Kendall Warm Springs dace (Rhinichthys osculus thermalis), a fish found nowhere else on Earth. Any change in the spring's flow, temperature, or sediment regime would imperil the entire species.
• Lime Creek–Green River Headwater Integrity: The area holds the Lime Creek–Green River headwaters and feeds Red Creek, South Fork Gypsum Creek, Moose Creek, and Dago Creek. Without a road network to deliver sediment to channels, these cold headwater streams sustain the gravel structure and clear, cold flow that downstream native Colorado River–basin fishes (including federally listed Bonytail, Humpback Chub, Colorado Pikeminnow, and Razorback Sucker) depend on through their range, and that supports mountain whitefish and rainbow trout fisheries on site.
• Subalpine Whitebark Pine Stands and Sagebrush–Aspen Connectivity: Northern Rockies Subalpine Woodland and Parkland, Rocky Mountain Dry Subalpine Spruce-Fir Forest, and the broader Intermountain Mountain Sagebrush Steppe / Rocky Mountain Aspen Forest mosaic remain connected without road-driven fragmentation. The roadless condition preserves the whitebark pine (Pinus albicaulis) seed-dispersal relationships with Clark's nutcracker, the high-elevation rock terrain used by black rosy-finch (IUCN endangered), and the open sagebrush–aspen winter and transitional habitat that grizzly bear, wapiti, mule deer, moose, and Canada lynx use across the year.

Potential Effects of Road Construction

• Direct Threat to Kendall Warm Spring Endemic Population: Road construction anywhere in the spring's source area would risk altering the spring's discharge, temperature, or chemistry — any of which would compromise the only known habitat of the Kendall Warm Springs dace. Construction-related sedimentation, hydraulic disturbance, fuel spills, and shoulder runoff would have no margin of safety for a single-stream endemic species. Recovery of this kind of habitat loss is not feasible at any timescale because the species occurs nowhere else.
• Sedimentation of Cold Headwater Streams: Cut-and-fill construction on the steep slopes above Red Creek, South Fork Gypsum Creek, Moose Creek, and Dago Creek would deliver chronic fine sediment to the Lime Creek and upper Green River channels during every snowmelt and convective storm. Fine sediment fills spawning gravels used by mountain whitefish and trout, suppresses macroinvertebrate production, and persists in the system for decades. Sediment moving downstream adds to the cumulative pressure already facing the Green/Colorado-system listed fishes.
• Fragmentation of Subalpine Habitat and Invasive Species Introduction: A road corridor through Rocky Mountain Lodgepole Pine Forest, Central Rockies Douglas-fir Forest, and Northern Rockies Subalpine Woodland and Parkland would slice the closed-canopy stands into smaller patches with sun- and wind-exposed edges. Edge effects accelerate windthrow and create conditions in which white pine blister rust and mountain pine beetle attack whitebark pine. Disturbed roadside soils and vehicle tires would carry cheatgrass and other non-native annuals into the Intermountain Mountain Sagebrush Steppe and Wyoming Basin Dwarf Sagebrush, converting native sagebrush–bunchgrass communities to fire-prone monocultures. The same corridor would extend human access into core habitat for grizzly bear and Canada lynx, both of which avoid road corridors and lose effective habitat far beyond the road's footprint.

The Little Sheep Mountain Inventoried Roadless Area covers 14,192 acres of the upper Green River country in the Bridger-Teton National Forest, with vehicle access from the Green River Road (Forest Road 091) running north out of Pinedale. Whiskey Grove Campground is the closest developed staging site, and the Green River Snowmobile Trailhead and Boat Launch provides the winter access point. Three groomed snowmobile routes — the N Snowmobile Trail (7SM680) at 25.4 miles, the CDST Snowmobile Trail (7SM660) at 26.5 miles, and the GL Snowmobile Trail (7SM650) at 5.9 miles — total roughly 58 miles of native-surface winter trail crossing the area, linking to the broader Continental Divide Snowmobile Trail system. In summer the same corridors serve as cross-country foot, horse, and stock travel routes, and dispersed camping is the standard pattern away from Whiskey Grove.

Fishing focuses on the upper Green River reaches accessible from the boat launch and adjacent Lime Creek tributaries — Red Creek, South Fork Gypsum Creek, Moose Creek, and Dago Creek. Rainbow trout (Oncorhynchus mykiss), mountain whitefish (Prosopium williamsoni), and mountain sculpin (Cottus punctulatus) hold in the cold reaches. Boat-launch access supports float-fishing on the upper Green. Wyoming Game and Fish regulations apply. Kendall Warm Spring itself and its outflow are closed to fishing and to any in-water disturbance under federal protections for the Endangered Kendall Warm Springs dace; visitors should observe the spring only from the bank and stay out of the water.

Hunting is a major fall use. The mosaic of sagebrush, aspen, lodgepole, and subalpine parkland on Little Sheep Mountain, Gypsum Hill, Gypsum Park, and Red Hill supports wapiti (Cervus canadensis), moose (Alces alces), mule deer (Odocoileus hemionus), and American black bear (Ursus americanus). Hunters typically pack in from Whiskey Grove or the Green River Road trailheads for multi-day fall trips. This is grizzly bear (Ursus arctos) country and food-storage discipline is required; grizzly is not a regulated game species. Wyoming general elk, deer, and moose seasons govern the area.

Birding is strong. The eBird hotspot at the nearby Green River Lake Campground has logged 112 species, and the same fauna moves through the Little Sheep Mountain area. Clark's nutcracker (Nucifraga columbiana) caches whitebark pine seeds across the high ridges. Sandhill crane (Antigone canadensis) calls carry across the Gypsum Park meadows. Barrow's goldeneye (Bucephala islandica), common merganser (Mergus merganser), red-breasted merganser (Mergus serrator), and American wigeon (Mareca americana) work the Brook Lake / Kendall Warm Spring open-water complex year-round, including in winter when surrounding water is frozen. Bald eagle (Haliaeetus leucocephalus) and osprey (Pandion haliaetus) hunt the upper Green. The black rosy-finch (Leucosticte atrata) — IUCN endangered — uses the alpine rock terrain at the upper edge of the area.

Winter recreation is the area's signature use. The 58 miles of groomed snowmobile trails put riders into the Continental Divide network from the Green River Snowmobile Trailhead. Cross-country and backcountry skiers use the same staging point for ski-in trips toward Gypsum Hill and Little Sheep Mountain. Photography centers on Kendall Warm Spring's steam against winter snow, the upper Green River canyon, and the Wind River Range views from the ridges.

Every one of these uses — multi-day pack-in hunting, undisturbed cold-water trout fishing in Lime Creek and the upper Green, intact subalpine bird and whitebark pine habitat for the Clark's nutcracker community, and the protected Kendall Warm Spring system — depends directly on the absence of roads through the interior. Road construction would shorten the pack-in experience to a day trip and place direct disturbance, sediment, and shoulder runoff in reach of a single-stream endemic species.